Middleware adds X-Powered-By header

[dimitrisfasoulas]

Using the default example and adding disable('x-power-by') :

const express = require('express');
const promMid = require('express-prometheus-middleware');
const app = express();

const PORT = 9091;
app.disable('x-powered-by');
app.use(promMid({
  metricsPath: '/metrics',
  collectDefaultMetrics: true,
  requestDurationBuckets: [0.1, 0.5, 1, 1.5],
}));

// curl -X GET localhost:9091/hello?name=Chuck%20Norris
app.get('/hello', (req, res) => {
  console.log('GET /hello');
  const { name = 'Anon' } = req.query;
  res.json({ message: `Hello, ${name}!` });
});

app.listen(PORT, () => {
  console.log(`Example api is listening on http://localhost:${PORT}`);
});

then do curl -i http://localhost:9091
you get

X-Powered-By: Express
...```

where if you remove the promMid then the header is removed.